There is no conclusive agreement about what the concept of intelligence really is. Some concepts of intelligence focused upon achievement, i.e., how much a person really knows relative to others in an age group, or aptitude orientated, i.e., the person?s ability to learn. Traditionally intelligence has been considered as a general trait ?g? where people would differ in the level they possess. However as separate abilities (e.g. verbal, memory, perceptual, and arithmetic) were recognized as intelligence, the concept of intelligence widened.